Apparatus for uniformly crimping filaments



Jan. 31, 1967 E. JOHNSON, J R

APPARATUS FOR UNIFORMLY CRIMPING FILAMENTS Filed June 29, 1965 RACK and IDLER GEAR INVENTOR.

5/5/70 Jamison, Jr

A f/omey' United States Patent 3,300,830 I APPARATUS FOR UNIFORMLY CRIMPING FILAMENTS Elisha Johnson, Jr., Charlotte, N.C., assignor to Fiber Industries, Inc., a corporation of Delaware Filed June 29, 1965, Ser. No. 467,952

2 Claims. (Cl. 281) This invention relates to an apparatus for uniformly crimping filaments. More particularly, this invention is directed to an improved device for crimping filaments wherein the rate of withdrawal of the filaments is constantly controlled to maintain a uniform weight in the setting chamber and to provide highly uniform crimps throughout the length of the filaments. 1

In the crimping of filaments, especially synthetic 'typ filaments, a comment technique which is used is known as stufiing box crimping wherein the filaments are folded upon themselves under pressure and heated to form a permanent crimp. A major diflicul-ty with this procedure relates to the fact that non-uniform crimping occurs due to the problem of maintaining control of all the variables such a maintaining constant volume in the setting chamber, maintaining a constant pressure in the setting chamber, maintaining a constant feed of filaments to the setting chamber and the like. In view of all the variables of stuffing box crimping, the primary requirement for a uniform crimping relates to the maintenance of a constant residence time of the filament in the heating Zone. It is also important in a continuous operation to make certain that the chamber never becomes entirely empty.

Various methods have been proposed for regulating the passage of the filaments through the stufling chamber. In one method, the use of a counter-pressure agent or stutfer which compresses the filaments up or down in the chamber from a desired position, actuates a variable speed motor which controls the feed rollers or the drawing-01f rollers. With this arrangement, however, it has been found that considerable and uncontrollable differences occur with regard to the residence time of any particular section of the filaments in the heating zone. It has also been found that undesirable fluctuations take place in the tension on the filaments or in the crimping intensity produced by the compressing means. i

In other known devices, either the rate at which the feed rollers supply the filaments to the stufiiing chamber or the speed of the drawing-off rollers are controlled by means of an on and off switchor by a variable motor having two preselected speeds which are operated by means of the counter-pressure agent. In the case of the on or off switch device, the slip motors which are usually used behave differently in response to slight changes in operating conditions such as hearing friction. In the case of two preselected speeds, it is difficult to determine and maintain the equilibrium conditions to start the process which is time consuming and wastefulf In the use of the two preselected speeds for withdrawing the-filaments, there is only limited control between the two speeds and if a disruption occurs, the difiiculty of producing the desired equilibrium condition is present again.

According to this invention a device which is simple and inexpensive is provided for crimping filaments using the stuffing box technique wherein the amount or weight of filaments in the setting chamber controls the withdrawal of the filaments by instantaneously adjusting the speed of the take-up or wind-up means to maintain the predetermined weight in the setting chamber. The use of the device of this invention provides a process for crimping wherein a constant residence time of the filaments in the setting chamber is obtained and highly uniform crimped filaments are provided. A distinct advantage of the device and process of this invention is provided in the case in which equilibrium conditions of the crimping operation can be obtained and maintained.

The nature of the invention will be better understood from the following description, taken in connection with the. accompanying drawing in which a specific embodiment has been set forth for purposes'of illustration. In the accompanying drawing, the filaments 10 are passed from a supply point (not pictured) at a constant rate through paired conveyor rolls'll and 12 into a crimping or stutter chamber 13 wherein the initial'folds of the filaments 10 occur. The folded filaments 10 passed from the crimping or stutter chamber 13 into a vertically movable setting chamber 14 which is separated from the stuffer chamber 13 and mounted on flexible mountings 15 and 16. This permits the setting chamber 14 to move up and down by means ofv a hinge within the limits provided by the flexible mountings 15 and 16. At the base of the setting chamber 14 is a fixed-constriction 17 attached thereto an adjustable screw 18 to provide the necessary constriction pressure to the filaments 10 in the setting chamber. There are heating means (not shown) in the setting chamber 14 which can provide heat in the temperature range from 25 C. to 250 C. for purposes of setting the crimp of the filaments. Attached to the setting chamber 14 is a counterbalanced weight 19 maintained by a line 20 around pulleys 21 and 22 to provide the desired resistance to the setting chamber 14 to balance said chamber at the appropriate place between the flexible mountings 15 and 16 under the desired weight conditions. A weight sensitive lever 23, attached to a spring means 24 is placed under tension in contact with setting chamber 14 in order that the lever 23 is movable with the movement of the setting chamber 14. Lever 23 is attached to an electrical sensing device 25 for example, a potentiometer so that lever 23 actuates the electrical sensing device 25 which in turn supplies or withdraws electric current to a variable speed motor 27 controlling proportionally the speed of the bobbin spindle 28 through take-up means or rollers 26 in relationship to the desired weight of the setting chamber 14. In the operation of this apparatus, a predetermined weight of the setting device 14 is established for heat setting the crimp of filaments 10. As the filaments are folded in setting chamber 14 and compressed by the fixed restriction 17, the Weight of the filaments will cause the setting chamber 14 to move from its top position toward its bottom'position and lever 23 will move accordingly. As the proper weight is obtained, the takeup mechanism 28 through the take up or rollers 26 will begin to withdraw the crimped filaments 10 from the setting chamber 14 around an idler roll 29. If the weight I of'thesetting chamber 14 begins to exceed the required nism 28 through the take-up or rollers 26 so that a constant weight of the setting chamber 19 is maintained. If the weight of the setting chamber 14 decreases below the desired predetermined weight, the setting chamber 14 will move up along with lever 23 which actuates the potentiometer controlling the motor which will proportionally decrease instantaneously the motor speed of the take-up mechanism 28 through the take-up or rollers 26. After equilibrium i.e. the desired constant weight of the setting chamber 14 is obtained, the control of withdrawal of the filaments can be carried out as described above with extreme accuracy and uniformity. Under equilibrium conditions of the crimping and heat setting conditions above, each of the filaments 10 and portions thereof are maintained in the setting chamber for a constant residency time so that a highly uniform crimped product is obtained.

The types of filaments which can be used in the device 3 I of this invention can include continuous synthetic filaments such as nylon 6, nylon 66, polyethylene terephthalate, polypropylene, acetate rayon, and the like and natural type fibers such as slivers of cotton, wool, and the like or combinations of natural and synthetic filaments or slivers.

The total denier of filaments which can be used herein can range from fine denier to heavy denier. Bythis proc .ess the uniformly crimped filaments of polyhexamethyl- 'eneaclipamide (nylon 66) in the total denier range from tures should exceed the'second order transition temperature and generally not exceed the softening or melting point of the filaments. In the use of wool slivers, suitable setting temperatures can be obtainedin the range from 80 C. to 150 C. After the heat setting step has occurred and the filaments are withdrawn from the setting chamber, the filaments can be cooled if desired to obtain the permanent crimp properties. The permanent crimp placed in the filaments can have a frequency from about 3 to as high as 50 crirnps per inch depending on the desired use of the filaments. The important aspect of the device of this invention relates to the fact that highly uniform crimps are obtained and maintained in the" final product. i

It is to be understood that the'fo-regoing description is merely illustrative and preferred embodiments of themvention of which many var'iationswmaybe made by those skilled in the art within the scope ofthe following claims without departing from the spirit thereof.

What is claimed is:

1. An apparatus for uniformly crimping filaments which comprises: a crimping chamber, a pairof feed rolls at onetend-of said crimping chamber to initiate the folding of said filaments through said crimping chamber, a flexible mounted setting-chamber vertically movable and separated from said.crimping chamber, said setting chamber located in such'relationship tosaid crimping chamber to'receive the partially folded filaments 'at one end, fixed compression means at the other end of said setting chamber to foldsaid filaments tightly against one anothen-aweight sensing'device'attached to said flexible mounted setting chamber, a potentiometer, -means attached to saidweight sensing device and said potentiometer to transfer changes in weight to changes in electric current, a take-up mechanism for withdrawal of said filaments from said setting'chamber wherein the speed of said take-up mechanism is instantaneously controlled by said potentiometer through saidmeans attached to said potentiometer and said Weight sensing device attached to said setting chamber in a manner so that 'as the'desired predetermined weight of filaments in said setting chamber is maintained, the desired speed of said take-up mechanism is 'maintained'and as the weight of said filaments becomes excessive as to the desired predetermined weight of said filaments, the speed of the take-up mechanism is proportionally increased to attain the desired predeter' mined weight with the additional proviso that as the Weight in said setting chamber falls below the desired predetermined weight, the speed of said take-up mechanism is proportionally decreased to attain the desired predetermined weight.

2. An apparatus for uniformly crimping filaments which comprises: a crimping chamber, a pair of feed rolls at one end of said crimping chamber to initiate the folding of said filaments through said crimping chamanother, a spring tensioned lever attached on one end to said spring mounted setting chamber and containing a rack on the other end of said spring tensioned lever which is movable with the movement of said spring mounted setting chamber, a potentiometer, an idler gear enmeshed with said rack attached to said spring tensioned lever and to said potentiometer to transfer changes in weight to changes in electric current, a take-up mechanism for withdrawal of said filaments from said setting chamber, wherein the speed of said take-up mechanism is instantaneously controlled by said potentiometer through said idler gear, rack and tensioner lever in a manner so that as thedesired predetermined'weight of filaments in said setting chamber is maintained, the desired speed of said take-up mechanism is maintained and as the weight of said filaments becomes excessive as to'the desired predetermined weight of said filaments, thespeed of the takeup mechanism is proportionally increased to attain the desired predetermined weight with the additional proviso that asthe weight in sa'id'setting chamber falls below the desired predetermined Weight, the speed of said take-up -mechar'ii sm is proportionally decreased to attain the desired predetermined weight.

References Cited by the Examiner UNITED STATES PATENTS 2,740,992 4/1956 Shattuck. l 2,805,449 9/-1957 Martin 19240 2,914,262 11/1959 Ludvigsen 242-45 XR 3,151,820 10/1964 Bahring et-al. 242-5512 3,153,837 10/1964 Schippers et-al. 28l 3,166,821 1/1965 Furlong 281 3,174,206 3/1965 Mattingly et al. 28l

Iwnicki et al. 28.1

"FOREIGN PATENTS 964,908 7/1964 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

1. AN APPARATUS FOR UNIFORMLY CRIMPING FILAMENTS WHICH COMPRISES: A CRIMPING CHAMBER, A PAIR OF FEED ROLLS AT ONE END OF SAID CRIMPING CHAMBER TO INITIATE THE FOLDING OF SAID FILAMENTS THROUGH SAID CRIMPING CHAMBER, A FLEXIBLE MOUNTED SETTING CHAMBER VERTICALLY MOVABLE AND SEPARATED FROM SAID CRIMPING CHAMBER, SAID SETTING CHAMBER LOCATED IN SUCH RELATONSHIP TO SAID CRIMPING CHAMBER TO RECEIVE THE PARTIALLY FOLDED FILAMENTS AT ONE END, FIXED COMPRESSION MEANS AT THE OTHER END OF SAID SETTING CHAMBER TO FOLD SAID FILAMENTS TIGHTLY AGAINST ONE ANOTHER, A WEIGHT SENSING DEVICE ATTACHED TO SAID FLEXIBLE MOUNTED SETTING CHAMBER, A POTENTIOMETER, MEANS ATTACHED TO SAID WEIGHT SENSING DEVICE AND SAID POTENTIOMETER TO TRANSFER CHANGES IN WEIGHT TO CHANGES IN ELECTRIC CURRENT, A TAKE-UP MECHANISM FOR WITHDRAWAL OF SAID FILAMENTS FROM SAID SETTING CHAMBER WHEREIN THE SPEED OF SAID TAKE-UP MECHANISM IS INSTANTANEOUSLY CONTROLLED BY SAID POTENTIOMETER THROUGH SAID MEANS ATTACHED TO SAID 